Engine break-in issues?

I believe I'm experiencing some issues with my freshly-built BP. I had a shop build the bottom end, clean the top end, and assemble the head to the block. Let me give you some more information about the build before explaining the "issue".

What's happening is I am getting smoke when and after pulling vacuum under decel. The engine appears to be "healthy" as it has good power, but I've driven it roughly 150 miles and through 2 oil changes of the Pennzoil 10w-30 conventional oil and it is still smoking under the conditions mentioned above. I pull a max of around 28" vacuum and have about 20psi oil pressure at idle, 40-50 when driving.

Please help/explain what may be going on, and what I may be able to do to fix this.

Here are some shots of the plugs. The first one is a close-up of what they all basically look like. The ceramic looked tinted a bit tan, and there was a small layer of black soot on most of the metal portions. They honestly look fine to me but I could be wrong. Any of the odd looking silver on the bottom edge, threads, and washers is just silver anti-sieze. If anything the ceramic on plugs for cylinders 2 and 3 were very slightly darker.